1. Field of the Invention
The present invention relates to a circular saw having a saw arm angle adjusting device, and more particularly to a circular saw having a saw arm angle adjusting device, wherein the user may directly operate the drive shaft, so as to operate the adjusting device for adjusting the angle of the saw arm relative to the base so that the user may adjust the angle of the saw arm easily and conveniently.
2. Description of the Related Art
A conventional circular saw in accordance with the prior art comprises a base, a saw arm mounted on the base, and a saw blade mounted on the saw arm. The saw arm may be moved toward the base for cutting the workpiece on the base by the rotating saw blade. The conventional circular saw also comprises an adjusting device for adjusting the angle of the saw arm relative to the base, so that the saw arm is inclined with the base. Thus, the cutting face of the workpiece may be cut to have an inclined shape. The adjusting device is usually mounted on the rear portion of the saw arm, so that the user has to move to the rear portion of the saw arm, to operate the adjusting device, thereby causing inconvenience to the user. In addition, the adjusting device may provide a larger angle adjusting function, and cannot be used to micro-adjust the angle of the saw arm relative to the base.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional adjusting device of the circular saw.
The primary objective of the present invention is to provide a circular saw having a saw arm angle adjusting device, wherein the distal end of the drive shaft is exposed outward from the bottom face of the base to face the user, so that the user may directly operate the drive shaft without having to move, so as to operate the adjusting device for adjusting the angle of the saw arm relative to the base so that the user may adjust the angle of the saw arm easily and conveniently.
Another objective of the present invention is to provide a circular saw having a saw arm angle adjusting device, wherein the gear portion of the driven unit having a smaller tooth number may be used to drive the first gear of the adjusting unit having a greater tooth number, and the second gear of the adjusting unit having a smaller tooth number may be used to drive the gear portion of the rotation shaft having a greater tooth number, thereby saving manual energy, and thereby capable of micro-adjusting the angle of the saw arm relative to the base.
In accordance with the present invention, there is provided a circular saw having a saw arm angle adjusting device, comprising a base, a saw arm, a rotation shaft mounted between the base and the saw arm, and an adjusting device mounted on the base for adjusting the angle of the saw arm, so that the saw arm may be pivoted through an angle, and may be positioned, wherein:
the rotation shaft is provided with a gear portion, and a fixing bolt is extended through the rotation shaft, and has one end provided with a fixing nut for fixing the rotation shaft to prevent rotation of the rotation shaft; and
the adjusting device includes:
a drive shaft, movable axially;
a drive unit, secured on one end of the drive shaft to move therewith, and having a first side formed with a first locking recess, and a second side formed with a second locking recess, for receiving and locking the fixing nut of the fixing bolt when the drive unit is moved to abut the fixing nut of the fixing bolt;
a driven unit, rotatably mounted on the base, the driven unit having one end provided with a locking block that may be inserted into the first locking recess of the drive unit when the drive unit is moved to abut the locking block of the driven unit, the driven unit having an outer wall provided with a gear portion; and
an adjusting unit, including a shaft rotatably mounted on the base, a first gear secured on a first end of the shaft and meshing with the gear portion of the driven unit, and a second gear secured on a second end of the shaft and meshing with the gear portion of the rotation shaft.
Preferably, the gear portion of the driven unit has a tooth number smaller than that of the first gear of the adjusting unit.
Preferably, the second gear of the adjusting unit has a tooth number smaller than that of the gear portion of the rotation shaft.
Preferably, the first side of the drive unit is formed with a receiving hole for receiving and securing the drive shaft, so that the drive unit may be moved with the drive shaft.
Preferably, the driven unit has an inner wall formed with a through hole for passage of the drive shaft.